Acute Reduction of Functional Mitral Regurgitation in Canine Model Using an Epicardial Device

Purpose: This study evaluated the short-term feasibility of a novel epicardial device that treats functional mitral regurgitation by simultaneously changing the mitral and the left ventricular geometry. Description: We implanted a prototype device that consists of 2 tissue anchors, a deflector, and a flexible tightening chord in 7 mongrel dogs with heart failure and functional mitral regurgitation induced by rapid ventricular pacing. Hemodynamic and echocardiographic data were obtained before and after device implantation. Evaluation: The device acutely reduced the mitral regurgitation grade from 3.2 ± 0.3 to 0.9 ± 0.5 (p < 0.001). Left ventricular end-diastolic volume (79.6 ± 23.6 to 61.2 ± 16.9 mL; p = 0.004) and end-systolic volume (63.1 ± 17.3 to 49.2 ± 12.3 mL; p = 0.006) decreased substantially. End-systolic elastance significantly increased from 1.9 ± 1.0 to 2.6 ± 1.4 mm Hg/mL (p = 0.02). Device implantation did not alter coronary perfusion. Conclusions: The epicardial device acutely reduced functional mitral regurgitation and improved left ventricular geometry. Further studies are required to demonstrate the long-term safety and efficacy of this concept.